An unmanned vehicle, which may also be referred to as an autonomous vehicle, is a vehicle capable of travel without a physically-present human operator on board. An unmanned vehicle may operate in a remote-control mode, in an autonomous mode, or in a partially autonomous mode.
When an unmanned vehicle operates in a remote-control mode, a pilot or driver that is at a remote location can control the unmanned vehicle by commands that are sent to the unmanned vehicle via a wireless link. When the unmanned vehicle operates in autonomous mode, the unmanned vehicle typically moves based on pre-programmed navigation waypoints, dynamic automation systems, or a combination of these. Further, some unmanned vehicles can operate in both a remote-control mode and an autonomous mode, and in some instances may do so simultaneously. For instance, a remote pilot or driver may wish to leave navigation to an autonomous system while manually performing another task, such as operating a mechanical system for picking up objects, as an example.
Various types of unmanned vehicles exist for different environments. For instance, unmanned vehicles may operate in the air, on the ground, underwater, or in space. Examples include quad-copters and tail-sitter unmanned aerial vehicles (UAVs), among others. Some unmanned vehicles operate in multi-environment operation. Examples of such hybrid unmanned vehicles include an amphibious craft that is capable of operation on land as well as on water, or a floatplane that is capable of landing on water as well as on land. Other examples are also possible.
Some conventional UAVs include an inner structural frame and an outer shell. The structural frame is built using a relatively strong, but also relatively heavy material (e.g., steel, aluminum, hard plastic, etc.), while the outer shell is made of a lighter filler material (e.g., closed cell foam or other light polymer). Typically, the structural frame is surrounded by the outer shell material.
With some conventional technologies, the structural frame is assembled or manufactured first. Next, the outer shell (e.g., closed cell foam) is sprayed onto the frame to give a shape to the UAV. The excess outer shell material is cut away to make room for cables, engines, avionics, and other subassemblies. However, in some cases removing the excess outer shell material may be difficult and time consuming, thus decreasing the efficiency of the overall UAV manufacturing process.
Furthermore, the material of the frame and the material of the outer shell may have different coefficients of thermal expansion (CTE). As a result, the frame and the outer shell expand and contract at different rates as the temperature of the environment changes causing manufacturing and assembly defects. In time, different expansion rates may lead to bending of the frame, and, for a sufficiently high number of the temperature cycles, to material fatigue and fracturing of the frame.
Accordingly, there remains a need for the systems and methods for assembling UAVs having improved efficiency of the assembly and reduced stress on the structural frame.